In the art of adjustable backboards and rims, a typical example is the use of a parallelogram connected between a support structure and the backboard and rim combination. The height of the backboard and rim is adjustable and locked in place. Various mechanisms have been used for the drive and the locking mechanisms. These generally have fallen in the categories of screw and bolt mechanisms, and rachet mechanisms. Although the parallelogram with the rachet mechanism has been very popular in the consumer market, the institutional market has different requirements. A parallelogram takes up valuable space because of the distance required from the support structure. Similarly, institutional backboards and rims are substantially heavier than consumer backboards and rims and therefore require a more substantial structure than a cantilevered parallelogram structure. A typical example of the screw and bolt drive parallelogram structures are shown by U.S. Pat. Nos. 3,765,676 to Bearson et al. and No. 4,395,040 to White.
Another method of adjusting the height of the backboard is a linear motion between the backboard structure and support. A typical example of a screw drive is U.S. Pat. No. 5,279,496 to Schroeder and patents cited of record therein. Other examples of a linear adjustment for ground mounted backboards include adjusting the mount itself. Typical examples are U.S. Pat. No. 5,156,395 to Smith and No. 3,598,406 to Robinson. These include screw as well as gears or rack and pinion drives.
Most of the prior art including screw drives and gear drives do not have any lock of the adjustment. Thus, during play, the adjustment mechanism can creep downwardly. One example of a lock mechanism is provided in U.S. Pat. No. 4,522,394 to Broussard. The gear 216 in cooperation with the ratchet 122 adjusts the height of the pole to which the backboard and rim is attached. Ball bearings 238 rest in opposed hemisphere dimples 226 and 236 on the gear and lock plate respectfully. The application of the force from the handle 220 causes the balls to ride out and unlock the gear. It should also be noted that a substantial force on the backboard could cause the gear 216 to rotate with respect to the lock 232 and therefore inadvertently unlock the apparatus. Thus, the prior art does not provide any positive lock to the drive mechanism of an adjustable backboard.
Other examples of locks for screw drives is radial screw element 32 on one of the rails in U.S. Pat. No. 2,916,288 to Chervenka. U.S. Pat. No. 2,986,395 includes a pin 70 in an aperture of the gear hub 58 to prevent unwanted rotation or height adjustment.